Carburetor



March 25, 1930. W. c. CARTER 197531.?9375 CARBURETOR Fld Feb. 18, 1928 Il UA /Qr roe/Vim lPatented Mar.. 25, 1930 UMTED STATES WILLIAM C. CARTER, OF FLINT, MICHIGAN CARBUBETQR Application led. February 18, 1928. Serial No. 255,313.

This invention relates to carburetors. One object of the invention is to provide Y a carburetor that has three suction amplifiers, and a choking device which is of such adesign that when it is rendered operative, the two amplifiers that are used in the rst and second stages of suction amplification will 'be automatically cut out of service or rendered inoperative.

Another object of the invention is to provide a carburetor of novel construction, in which the high suction existing in the intake above the throttle valve, 4when the engine is not operating under a heavy load, is utilized to retard or diminish the flow of fuel to the fuel supplying device or devices of the carburetor at such times. Other objects and desirable features of my invention will be hereinafter pointed out.

l have herein illustrated my present invention embodied in a carburetor provided with some of the features of the carburetor described in my pending application for patent Serial No. 226,684, filed October 17, 1927 but modified so as to have three stages of suction amplification. I wishfit to be understood, however, that certain features of my present invention are applicable to various other types and kinds of carburetors.

Figure 1 of the drawings is a vertical sectional view of a carburetor embodying my present invention; and

Figure 2 is a horizontal sectional view, taken on the line 2-2 of Figure 1, looking lin the direction indicated by the arrows.

Briefly described, the carburetor herein illustrated comprises a well for holding an accelerating charge of liquid fuel which isl in readiness to be drawn into the main passageway of the carburetor. in the event the throttle valve is opened suddenly, a liquid fueltube or by-pass leading from a supply of liquid fuel and arranged with its upper end communicating with the main passageway of the carburetor adjacent the throttle valve in such a manner that it will supply fuel to said passageway at idle speeds and slow speeds; a liquid fuel supplying device,

preferably a nozzle provided with a fixed dis- 5 charge orifice; a plurality of suction amplitiers for producing three stages of suction amplification, according to the position of the throttle valve; a choking device arranged so that it can be actuated to cut out of servicethe suction amplifiers used in the first and second stages of suction amplification; and a means for retarding the flow of fuel to said nozzle during the third stage of suction amplification when the maximum suction is being exerted on the fuel nozzle. The carburetor is also preferably constructed in such a way that the relatively high suction which exists in the intake above the throttle valve when the engine is not operating under a heavy load, is utilized to diminish or retard the flow of liquid fuel to the fuel supplying device or devices of the carburetor at such times, thereby producing a carburetor that is economical in the consumption of fuel.

In the accom anying drawings which illustrate the pre erred form of my invention, A designates the body casting of the carburetor which is provided :with a straight, vertically-disposed bore 1 that,l constitutes the main passageway of the carburetor, 2 designates a throttle valve which is arranged in said main passageway adjacent the upper end of same, 3 designates an air chamber which communicates with the lower end of said main pasageway, 4: designates -a depending cylindrical portion on the body casting that serves as a guide for an annular float 5 in the bowl 6 that constitutes the float chamber of the carburetor, 7 designates an accelerating well or reservoir in the de ending portion 4 of the body casting, 8 esignates a tubular member projecting upwardly from the bottom of said well and provided at its lower end with openings, preferably vertically-disposed slots 9 of such length that the upper ends of same terminate above the normal level of the fuel in the float chamber, represented by the dot and dash line in Figure 1, `and 10 designates a fuel supplying device, preferably a nozzle, that projects upwardly into the tubular member 8 at the lower end of the same. Liquid fuel is suplied to the nozzle 10 from the float chamber by a duct 11 of relatively large'cross-sectional area, and liquid fuel is supplied from according to the position of the throttlevalve 2, the amplifier B that is used to produce the high stage of suction amplification f 10 preferably consisting of a venturi arranged inside of the tubular member 8, with its contracted portion surrounding the discharge portion of the nozzle 10, the amplifier C that is used to produce the intermediate stage of suction amplification preferably consisting of a venturi arran ed in concentric relation with the ampli er B,with the contracted portion of said venturi C surrounding the discharge end of the amplifier B,

and theamplier D preferably consisting of a venturi arranged in the main passageway 1, with the contracted portion of said venturi D normally surrounding the upper end or dischar e end of the amplifier C.

The dow stage suction amplifier D is mounted in the passageway 1 in such a way that it can be moved towards and away from a cup-shaped member 14 arranged at the upper end of the tubular member 8, so as to reduce or cutoff the admission of air to the main passageway 1 of the carburetor, and

thus constitute a choking device that is used to'facilitate the starting of the engine when it is cold. The intermediate stage suction amplifier C is carried by the cup 14 and is combined with the same in such a manner that when the amplifier D is spaced away from the cup 14, air can flow downwardly over the upper edge of said cup and then reverse and flow upwardly through the amplifier C. One convenient way of combiningthe amplifier C with the cup 14 is to connect said amplifier to a horizontally-disposed flange 15 on the inner side of the cup 14 that is provided with air holes 16, as shown in Figure 2. Any suitable means can be used to move the amplifier D towards and away from the cup 14, the means herein illustrated for this purpose consisting of a rotatable device 17 mounted in the body casting of the carburetor and provided at its inner end with an eccentricallydisposed pin 18 that enters a hole in the side of the amplifier D. The device 17 is provided with an actuating lever 19 and also with a torsion spring 20 or other suitable means that will normally exert pressure on the device 17 in a direction to hold the movable'element D of the choking device inits wide open or inactive position, as shown in Figure 1. In view of the fact'that the intermediate stage'suction amplifier C is arranged inside of the amplifier D, and is carried by the cup 14 whose top edge co-operates with the bottom edge of the amplifier to form the space through which air travels to both of the amplifiers C and D, it will be seen that when said choking device is rendered operative by moving the amplifier D downwardly into engagement with the upper edge of the cup 14, the two amplifiers C and D that are 'used to produce the intermediate stage and the low stage of suction amplification will be automatically cut out of service, thus leaving only .the high stage suction amplifier B operative.

A fuel tube 21, which is of the 'same general design and arrangement as the fuel tube of the carburetor illustrated in my pending application for patent previously referred to,

is mounted in the body casting A of the car-A depending portion 4 of the body casting, ar-

rangedA with its lower end communicating with the shallow chamber 7, and with its upper end communicating with a fuel passageway 23 formed in a removable plug 24 in the body casting A, said fuel passageway 23 having a lateral inlet 23 and also an outlet, shown in broken lines in Figure 1, that leads to the lower end of the fuel tube 21.' 'Air is admitted to the lower end of the fuel tube 21 by an air port 25 formed in the plug 24 in such a manner that air will fiow through the fuel passageway 23 in the plug 24 and then enter the lower end of the fuel tube 21.

The upper end portion of the fuel tube 21 is so formed that when the throttle valve 2 is closed or only partly open, fuel will pass.

ioo

from the upper end of said tube into the main passageway 1 at a point above the throttle. valve, and alr. will enter said tube from the:l main passageway 1 at a point below ther throttle valve, and thus cut down or reduce the suction that is exerted on the upper end of the fuel tube 21 by the high vacuum which then exists in the intake of the engine. lVhen the throttle valve is moved forwardly away from its idle position, the admission of air from the passageway 1 to thev upper end of the tube 21 is cut olf, thereby causingthe full force of the vacuum which then exists in the intake of the engine to be exerted on the upper end of the fuel tube `21 or a lateral fuel discharge opening in the same. ln the carburetor herein illustrated the fuel tube 21 is open at its upper end and provided with a vertically-disposed slot 26 that is presented to the main passageway 1, said slot 26 being so proportioned that when the throttle valve is in its closed position, the top portion of said slot will be positioned above the throttle valve, and the bottom portion Vof said slot will be positioned below the throttle valve.

When the engine is idling with the throttle valve in its closed position, some liquid fuel mixed with air will be drawn upwardly through the tube 21 and discharged from the upper end of said tube into the main passageway 1, at a point above the throttle valve, due to the fact that the vacuum in the intake of the engine produces a suction in the tube 21 that is exerted on the passageway 23 in the plug 24 to which air and fuel are supplied by the air port 25 and the fuel duct 22, respectively. After the throttle valve has been moved into such a position that the lower end portion of the slot 26 Ain the upper end of the tube 2l will be positioned above the throttle valve, the high .vacuum which exists in the intake of the engine when the throttle valve is partly openwill become operative for drawing fuel upwardly through the tube 21, thus increasing the amount of `fuel which said tube introduces into the main passageway 1. From the foregoing it will be'seen that the high vacuum which exists in the intake above the throttle valve when the engine is not operating under a heavy load, is exerted directly on the fuel tube 21, and it will also be seen that the suction in the -tube 21 will be varied by a change in the .-position of the throttle valve. t

In a certain position of the throttle valve air is drawn upwardly into said main passageway 1 through the annular opening at the contracted portion of the low stage suction amplifier D at such a velocity as to create a suction inside ofthe suction amplifier B that will draw air downwardly into the well 7, and thence inwardly through the vertically-disposed slots 9 in the lower end of the tubular member 8, said air. picking up or absorbing more or less of the fuel in the well 7 and carrying it upwardly through the concentricaily-arranged suction amplifiers into the main passageway 1 of the carburetor. When the throttle valve reaches such a position as to cause sufficient air to travel through the well 7 to keep said welldry, the air which is drawn upwardly through the annular space between the lower end of saidy amplifier C and the upper end of the amplitier B which it surrounds, creates a suction on the nozzle 10 of suihcient intensity to cause fuel to be drawn out of said nozzle and carried upwardly into'the main passageway l. As the throttle valve continues to move towards its o en position, the velocity of the air that is rawn into the lower end of the high stage suction amplifier B through the vertical slots 9 in the tubular member 8 is materiallyv increased, e thereb causing the 'fuel which is drawn out of t e nozzle 10 to be eifectively broken up and mixed with air.'

tion in which the air that is drawn upwardly through the contracted portion of the suction amplifier D produces suiiicient suction to cause air to travel through the well 7 and keep said well dry; there is another stage in which the air that is drawn upwardly through the contracted portion of the amplitier C produces a suction that causes fuel to be drawn upwardly out of said nozzle l0 and discharged into the main passageway 1 of the carburetor, and there is still another stage in which air traveling at a very high velocity rushes upwardly through the annular space between the contracted portion of the ampliier B and the discharge portion of the nozzle 10, with the result that the fuel discharged from the nozzle will be broken up and thoroughly mixed with the air that is enteringthe main passageway 4l of the carburetor.

he fuel discharge orifice 10"L of the nozzle 10 is made large enough to prevent it from becoming easily clogged or stopped. up by foreign matter in the fuel that flows through the same, and in order to prevent said orifice from supplying an excessive amount of fuel at the high stage of suction ampliiication, when air 1s travelin at a high velocity upwardly around the ischarge portion of the nozzle, lf provide the carburetor with a means that effectively retards or cuts down the supply of fuel to the nozzle 10 at such times. 'lhe means that I have herein illustrated for accomplishing this result consists of an air port or passageway 27 that establishes communication between the upper portion of the oat chamber of the carburetor and the upper portion of the well 7. During the high stage of suction amplification the air that is drawn downwardly through the well 7 and thence upwardly through the suction ampliiier l5, travels at such a high velocity that it will suck air out of the upper portion or" the float chamber and produce a partial vacuum in the iioa't chamber above the surface of the fuel therein, therebyexerting a suicient upward pull on the fuel in the iioat chamber to retard the flow of the fuel to the nozzle l0. Accordingly, notwithstanding the fact that said nozzle is provided with a relatively large fuel discharge orifice 10, said orifice will not supplly an excessive quantity of fuel during the lgh stage of suction anipliiication, because at such times the flow of the fuel from the float chamber to the nozzle 10 is choked, reduced or diminished by the minus pressure which is created in the upper portion of the iioat chamber by travels downwardly through the well 7, and then reverses and ows upwardly through the high stage suction amplifier '15. rthe passageway Y 27 performs another function, in that it balances the suction on the fuel oriiice 12 that leads from the float chamber and permits the fuel to iiow by gravity from the tloat chamber to the well 7 and to the shallow the stream of air which,

Another feature oi m invention which l ybelieve to be novel is ma ing use of the high suction that exists in the main passageway l of the carburetor, above the throttle valve, when the engine is not operating under a heavy load, to checlT the flow el fuel 1from the idoat chamber to the fuel supplying device or devices et the carburetor, thereby tending to malte the carburetor economical in the consumption of fuel by preventing a rich supply oi fuel at a time when it is not need-ed, ln the carburetor herein shown li obtain this highly desirable result by arranging an air passageway 28 between the upper portion ed the lioat .chamber of the carburetor and the :tuel 'tube 2l, the air passageway 28 beinp,r herein illustrated as leading from the underside of the top wall ol the iloat chamber to an annular groove 28 in the exterior of the. plug 2d which registers with the lower end oi the fuel tube 2l, lit will, ot course, be understood that the passageway Q8 is so proportioned or designed that the suction in the tube 21 will produce a minus pressure in the float chamber above the level of the fuel in same at the same time said suction is causing fuel to be drawn upwardly through the fuel passageway 22. @ne means that can be used to regu late the suction which the tube 2l exerts on the iloat chamber above the level of the fuel therein, consists oif an air bleeder 28h for admitting air to the passageway 28. As previously stated, the high suction that exists in the intake above the throttle valve 2, when said valve is in its closed or partly closed position, is exerted on the fuel tube 2l, andas the air 'passageway 28 communicates with the lower end ot said fuel tube, this high suction in the intake will tend to produce a minus pressure in the Heat chamber above the level oi the fuel therein, with the result that the flow of fuel to the device which at this period in the cycle ol operations of the carburetor constitutes the source of fuel supply, is checked or retarded. As soon as the vacuum in the intake above the throttle valve diminishes, by a change in the position of the throttle valve, the upward pull which the suction in the tube 2l exerts on the body of fuel in the float chamber diminishes. with the result that the fuel in the float chamber is no longer subjected to the inuence of the means that tends to retard the flow of the same from the float chamber when the engine is not operating nnder a heavy load. Bearing in mind that a change in the position of the throttle valve 2 eects a change in the degree of suction of the tube 2l, it will be seen that in such a carburetor the movement of the throttle valve from its open towards its closed position causes the fuel in the float chamber to be subjected to the influence of a means that tends to vretard the liow of the fuel from the float chamber to the fuel supplying device or devices of the carburetor, and that the movement of the throttle valve from its closed towards its open position automatically renders this retardino means inoperative or inei'ective.

la View of the fact that u is highly desirable to have the fuel low freely from the float chamber when the engine is cold, l provide the carburetor with a controlling valve 29 for the passageway 28 which is so constructed and arranged that it will remain closed when the carburetor is cold, and will open automatically when the carburetor is warmed by the heat that radiates from the engine. Any suitable type or kind of thermostat can be used for controlling the valve 29, such, for example, as a lever 30 formed from metals having different co-efiicients et expansion, and connected at one end by means of a fastening device 31 to the underside of the top wall of the doat chamber, the valve 29 being mounted on the tree end of said lever, as shown in ljligure l. When said lever becomes warm it will flex in a direction to open the valve 29 and hold it open, and when said lever thereafter cools oil, it will dex in the opposite direction to closesaid valve.

llaving thus described my invention, what l' claim as new and desire to secure by Letters Patent is:

'l2 A carburetor provided with an accelerating well, a tubular member projecting upwardly through said well, substantially vertically-disposed slots in the lower end portion ot said member, projecting upwardly from. the bottom of the well and terminating 'at a point above the normal level of the fuel in the well, whereby air and fuel can pass simultaneously from the well into said tubular member, a fuel supplying device arranged inside oi"- said tubular member, a suction am-a phier associated with said fuel supplying device for increasing the velocity of the air owing from said well into said tubular member at one stage of the cycle of opera tions ot the carburetor, and a passageway for establishing communication between said weiland the oat chamber above the level of the luel in said chamber.

f. il carburetor provided with a main pas sageway, a throttle valve for said passageway, a liquid fuel supplying" devil' 2:, a plu rahty of tubular suction amplifiers arranged in concentric relation with each other between said throttle valve and fuel suppl ing device, for producing1 dillerent stages o velocity of the air that draws fuel out vot said device, two of said ampliers having a com mon air inlet, and means for moving one of said amplifiers to close said inlet to facilitate easy starting of the engine on which the carburetor is used.

5 3. A carburetor provided with a liquid fuel supplying device, three tubular suction amplifiers arranged in concentric relation :for producing different stages of velocityvof the air 'that is used to draw fuelout of said dem vice, means for moving one of said suction 45 purpose described.

amplifiers relatively to the one located adjacent the same, and a part combined with said adjacentamplilier that co-operates with the movable ampliiier to render both'of said 5 amplitiers inoperative or ineffective to facilitate starting the engine on which the carburetor'is used. f

et. fl carburetor provided with a main pasl sageway, a 'fuel supplying device, a throttle 20 valve in said passageway, three suction amplifiers arran ed in concentric relation for producing di erent stages of velocity of the air that is used to draw fuel from said device, the low stage amplifier being movably g5 vmounted in the main passageway below the throttle valve, and a part combined with the intermediate amplilier that co-operates with the low stage amplier to cut both of said ampliiiers'out of service so as to' facilitate 30 starting the engine on which the carburetor is used. l v

5, A carburetor provided with a main passageway, a fuel supplying device, a plurality oi' tubular suction amplifiers arranged in 135 concentric relation for producing different stages of velocity of the air that isnsed to draw :fuel from said device, a rsubstantially cup-shaped member on the intermediate stage amplifier that is normally spaced away o from the low stage amplifier so as to provide a passageway through 'whicb'air is admitted to both of said ampliiers, and means for movin lthe low stage amplier towards and away :tr-om said cup-shaped member, for the WILLIAM C. @ARTER 

